1. The resulting condition of an employee who:
(a) Has a preexisting condition from a cause or origin that did not arise out of and in the course of the employee’s current or past employment; and
(b) Subsequently contracts an occupational disease which aggravates, precipitates or accelerates the preexisting condition,
Ê shall be deemed to be an occupational disease that is compensable pursuant to the provisions of chapters 616A to 617, inclusive, of NRS, unless the insurer can prove by a preponderance of the evidence that the occupational disease is not a substantial contributing cause of the resulting condition.
2. The resulting condition of an employee who:
(a) Contracts an occupational disease; and
(b) Subsequently aggravates, precipitates or accelerates the occupational disease in a manner that does not arise out of and in the course of his or her employment,
Ê shall be deemed to be an occupational disease that is compensable pursuant to the provisions of chapters 616A to 617, inclusive, of NRS, unless the insurer can prove by a preponderance of the evidence that the occupational disease is not a substantial contributing cause of the resulting condition.